'use client';

import { zodResolver } from '@hookform/resolvers/zod';
import { ChevronDown, Loader2, Sparkles } from 'lucide-react';
import { useRouter, useSearchParams } from 'next/navigation';
import { useTranslations } from 'next-intl';
import { useState } from 'react';
import { useForm } from 'react-hook-form';
import { OAuthButtons } from '@/components/auth/oauth-buttons';
import { Badge } from '@/components/ui/badge';
import { Button } from '@/components/ui/button';
import { Card, CardContent, CardDescription, CardFooter, CardHeader, CardTitle } from '@/components/ui/card';
import { Input } from '@/components/ui/input';
import { Label } from '@/components/ui/label';
import { Link } from '@/i18n/navigation';
import { useAuthStore } from '@/lib/auth-store';
import { loginSchema, type LoginFormData } from '@/lib/validations/auth';

const DEMO_PASSWORD = 'Velik@2026';

const DEMO_ACCOUNTS: { phone: string; name: string; role: 'ADMIN' | 'AGENT' | 'SELLER' | 'BUYER'; badgeClass: string }[] = [
  { phone: '+84876677771', name: 'Hồ Ngọc Hải', role: 'ADMIN', badgeClass: 'bg-red-500/10 text-red-600 border-red-500/20' },
  { phone: '+84900000002', name: 'Nguyễn Văn An', role: 'AGENT', badgeClass: 'bg-blue-500/10 text-blue-600 border-blue-500/20' },
  { phone: '+84900000005', name: 'Phạm Đức Dũng', role: 'SELLER', badgeClass: 'bg-amber-500/10 text-amber-600 border-amber-500/20' },
  { phone: '+84900000004', name: 'Lê Minh Cường', role: 'BUYER', badgeClass: 'bg-emerald-500/10 text-emerald-600 border-emerald-500/20' },
];

export default function LoginPage() {
  const router = useRouter();
  const searchParams = useSearchParams();
  const { login, isLoading, error, clearError } = useAuthStore();
  const [showPassword, setShowPassword] = useState(false);
  const [demoOpen, setDemoOpen] = useState(true);
  const t = useTranslations('auth');

  const oauthError = searchParams.get('error');
  const oauthErrorMessage = oauthError
    ? t(`oauthErrors.${oauthError}` as Parameters<typeof t>[0]) ?? t('oauthErrors.default')
    : null;

  const {
    register,
    handleSubmit,
    setValue,
    formState: { errors },
  } = useForm<LoginFormData>({
    resolver: zodResolver(loginSchema),
  });

  const fillDemoAccount = (phone: string) => {
    setValue('phone', phone, { shouldValidate: true });
    setValue('password', DEMO_PASSWORD, { shouldValidate: true });
    clearError();
  };

  const onSubmit = async (data: LoginFormData) => {
    try {
      await login(data);
      router.push('/');
    } catch {
      // Error is handled by the store
    }
  };

  return (
    <Card>
      <CardHeader className="space-y-1 text-center">
        <CardTitle className="text-2xl font-bold">{t('loginTitle')}</CardTitle>
        <CardDescription>{t('loginDescription')}</CardDescription>
      </CardHeader>
      <CardContent>
        {/* Demo accounts panel — MVP only */}
        <div className="mb-4 rounded-lg border border-primary/20 bg-primary/5">
          <button
            type="button"
            onClick={() => setDemoOpen(!demoOpen)}
            className="flex w-full items-center justify-between px-3 py-2 text-sm font-medium"
            aria-expanded={demoOpen}
          >
            <span className="inline-flex items-center gap-2">
              <Sparkles className="h-4 w-4 text-primary" aria-hidden="true" />
              {t('demoAccountsTitle')}
            </span>
            <ChevronDown
              className={`h-4 w-4 text-muted-foreground transition-transform ${demoOpen ? 'rotate-180' : ''}`}
              aria-hidden="true"
            />
          </button>
          {demoOpen && (
            <div className="space-y-2 border-t border-primary/20 p-3">
              <p className="text-xs text-muted-foreground">
                {t('demoAccountsHint')} <code className="rounded bg-muted px-1 py-0.5 font-mono text-xs">{DEMO_PASSWORD}</code>
              </p>
              <ul className="flex flex-col gap-1.5">
                {DEMO_ACCOUNTS.map((acc) => (
                  <li key={acc.phone}>
                    <button
                      type="button"
                      onClick={() => fillDemoAccount(acc.phone)}
                      className="flex w-full items-center gap-2 rounded-md border bg-card px-2.5 py-1.5 text-left text-xs transition-colors hover:border-primary/40 hover:bg-primary/5"
                    >
                      <Badge variant="outline" className={`shrink-0 ${acc.badgeClass}`}>
                        {acc.role}
                      </Badge>
                      <span className="flex-1 truncate font-medium">{acc.name}</span>
                      <span className="font-mono text-muted-foreground">{acc.phone}</span>
                    </button>
                  </li>
                ))}
              </ul>
            </div>
          )}
        </div>

        <form onSubmit={handleSubmit(onSubmit)} className="space-y-4" noValidate>
          {oauthErrorMessage && (
            <div className="rounded-md bg-destructive/10 p-3 text-sm text-destructive" role="alert">
              {oauthErrorMessage}
            </div>
          )}
          {error && (
            <div className="rounded-md bg-destructive/10 p-3 text-sm text-destructive" role="alert">
              {error}
              <button type="button" onClick={clearError} className="ml-2 font-medium underline">
                {t('dismiss')}
              </button>
            </div>
          )}

          <div className="space-y-2">
            <Label htmlFor="phone">{t('phone')}</Label>
            <Input
              id="phone"
              type="tel"
              placeholder={t('phonePlaceholder')}
              autoComplete="tel"
              aria-describedby={errors.phone ? 'phone-error' : undefined}
              aria-invalid={!!errors.phone}
              {...register('phone')}
            />
            {errors.phone && (
              <p id="phone-error" className="text-sm text-destructive" role="alert">{errors.phone.message}</p>
            )}
          </div>

          <div className="space-y-2">
            <div className="flex items-center justify-between">
              <Label htmlFor="password">{t('password')}</Label>
              <button
                type="button"
                className="text-xs text-muted-foreground hover:text-primary"
                onClick={() => setShowPassword(!showPassword)}
                aria-label={showPassword ? t('hidePassword') : t('showPassword')}
              >
                {showPassword ? t('hidePassword') : t('showPassword')}
              </button>
            </div>
            <Input
              id="password"
              type={showPassword ? 'text' : 'password'}
              placeholder={t('passwordPlaceholder')}
              autoComplete="current-password"
              aria-describedby={errors.password ? 'password-error' : undefined}
              aria-invalid={!!errors.password}
              {...register('password')}
            />
            {errors.password && (
              <p id="password-error" className="text-sm text-destructive" role="alert">{errors.password.message}</p>
            )}
          </div>

          <Button type="submit" className="w-full" disabled={isLoading}>
            {isLoading && <Loader2 className="mr-2 h-4 w-4 animate-spin" aria-hidden="true" />}
            {t('loginButton')}
          </Button>
        </form>

        <div className="relative my-4">
          <div className="absolute inset-0 flex items-center">
            <span className="w-full border-t" />
          </div>
          <div className="relative flex justify-center text-xs uppercase">
            <span className="bg-card px-2 text-muted-foreground">{t('orLoginWith')}</span>
          </div>
        </div>

        <OAuthButtons />
      </CardContent>
      <CardFooter className="justify-center">
        <p className="text-sm text-muted-foreground">
          {t('noAccount')}{' '}
          <Link href="/register" className="font-medium text-primary hover:underline">
            {t('registerLink')}
          </Link>
        </p>
      </CardFooter>
    </Card>
  );
}